Neurology Flashcards
What condition is giant cell arteritis associated with?
Polymyalgia rheumatica
Causes of cauda equina syndrome?
- herniated disc
- tumours (metastasis)
- spondylolisthesis (anterior displacement of a vertebra)
- abscess
- trauma
What do the nerves of the cauda equina supply?
- sensation to the perineum, bladder and rectum
- motor innervation to lower limbs and anal & urethral sphincters
- parasympathetic innervation of the bladder and rectum
Nerve roots of the cauda equina?
- L3-5
- S1-5
- coccygeal nerves
Red flags for cauda equina syndrome?
- saddle anaesthesia (perineum)
- loss of sensation in bladder / rectum
- urinary retention / incontinence
- faecal incontinence
- bilateral sciatica
- bilateral / severe motor weakness in legs
- reduced anal tone
Mechanism of action of neostigmine / pyridostigmine?
Blocks active site of acetylcholinesterase, increasing the amount of acetylcholine available to the post-synaptic membrane.
What is alteplase?
Thrombolytic drug used to treat acute ischaemic stroke (also STEMI and PE).
Mechanism of action of alteplase?
Converts plasminogen to plasmin, resulting in the lysis of fibrin.
Recommended time window for alteplase after acute ischaemic stroke?
< 4.5 after symptom onset.
What type of haemorrhage has a lucid interval?
Extradural haemorrhage
Triggering factors for migraine?
- CHeese
- Oral contraceptive pill
- Caffeine
- alcohOL
- Anxiety
- Travel
- Exercise
- (chocolate)
First line investigation for ischaemic stroke?
CT head
Definition of ischaemic stroke?
Rapid onset of neurological impairment, lasting greater than 24 hours (or leading to death). Due to reduced / absent blood supply to an area of the brain leading to death of tissues.
Initial treatment for ischaemic stroke?
300mg aspirin
What is the pathophysiology of Parkinson’s disease?
- progressive neurodegeneration of dopaminergic neurones in the substantia nigra
- this leads to dopamine deficiency, resulting in impaired initiation of movements
- aggregation of alpha-synuclein forms Lewy bodies
Signs of Parkinson’s?
- bradykinesia
- rigidity
- resting tremor
- postural instability
- shuffling gait
- expressionless face
Eye movement disorder in Parkinson’s
Conjugate gaze disorder
How is Parkinson’s investigated?
- PET scan with fluorodopa (shows decreased dopamine uptake in the substantia nigra)
- MRI brain
- DaTscan (type of SPECT to distinguish between Parkinson’s and essential tremor)
- serum ceruloplasmin / 24 hr urinary copper (exclude Wilson’s disease)
What is SPECT?
single-photon emission computed tomography
What is PET?
positron emission tomography
Differentials for Parkinson’s?
- Wilson’s disease
- essential tremor
- drug-induced parkinsonism
Pharmacological management of Parkinson’s?
- Levodopa (converted to dopamine)
- dopamine agonists
- MAO-B (monoamine oxidase) inhibitors
Non-pharmacological management of Parkinson’s?
- deep brain stimulation
- physiotherapy
- speech and language therapy
Complications of Parkinson’s?
- dementia
- depression
- sleep disorders
- falls
- dyskinesia due to medications
In what population of patients should sodium valproate not be used for seizures?
Females of child-bearing age, due to teratogenic effects.
First line treatment for new onset GTCS?
- lamotrigine
- topiramate
- oxcarbazepine
- levetiracetam
Side effects of long term levodopa use?
dyskinesia
Initial investigation for subarachnoid haemorrhage?
CT head
Investigation for SA haemorrhage if CT head is negative?
lumbar puncture
How is Guillain-Barre syndrome treated?
- IV immunoglobulin
- plasmapheresis (plasma exchange)
What is the only disease-modifying drug for MND?
Riluzole (anti-glutamate medication).
Investigations for myasthenia gravis?
- serum anti-AChR antibodies / anti-MuSK antibodies
- repetitive nerve stimulation
- ice pack test (improves ptosis)
- CT / MRI chest - thymus gland assessment
How is the thymus involved in myasthenia gravis?
- 70% of patients have thymic follicular hyperplasia
- 10% have thymoma
Initial presentation of myasthenia gravis vs LEMS?
- in myasthenia gravis, extra-ocular involvement is the most common initial presentation
- in LEMS, weakness of limbs is the most common initial presentation
Definition of transient ischaemic attack?
A transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia without acute infarction.
Sudden onset, lasts from a few minutes to 24 hours.
What is meant by crescendo TIA?
2 or more TIAs in a week - has a high risk of developing into stroke.
What causes TIA?
- thrombosis - due to atherosclerosis or small vessel disease (sickle cell anaemia, vasculitis)
- emboli - due to AF or carotid artery disease
- dissection (usually carotid) - may be spontaneous or secondary to trauma
Risk factors for TIA?
- smoking
- diabetes
- hypertension
- hypercholesterolaemia
- obesity
- AF
- carotid artery disease
- advancing age
- thrombophilic disorders (anti-phospholipid syndrome)
- sickle cell anaemia
- vasculitis
Pathophysiology of TIA?
Transient reduction in blood flow to an area of cerebral tissue, resulting in ischaemia causing focal neurological symptoms.
Clinical manifestations of TIA?
- unilateral muscle weakness
- unilateral sensory loss
- dysphasia
- ataxia / incoordination / vertigo
- amaurosis fugax
- homonymous hemianopia
- cranial nerve palsies
Investigations for TIA?
- clinical diagnosis
- head CT / MRI to rule out haemorrhage or infarction
- ABCD2 score to calculate stroke risk
- carotid dopplers (if patient is a candidate for carotid endarterectomy)
- lipid profile
- clotting profile (prothrombin time)
- ECG
What is the ABCD2 score?
Estimates risk of stroke following TIA.
Differentials for TIA?
- stroke
- hypoglycaemia
- seizure with Todd’s paralysis
- complex migraine
- space-occupying lesion
Acute TIA management?
- assessment in specialist clinic on the day / next day
- calculate stroke risk (ABCD2 score)
- 300mg aspirin for 2 weeks
- DOAC for AF (instead of aspirin)
- consider carotid stenting / endarterectomy
What is carotid endarterectomy?
Surgery to remove plaque within carotid arteries?
When is carotid endarterectomy indicated?
If carotid artery is over 70% stenosed.
Long term prevention after TIA?
- 75mg clopidogrel (after two weeks of aspirin)
- anti-hypertensives
- statin therapy
- diabetic control
- lifestyle measures (physical activity, smoking cessation, diet optimisation, reduce alcohol)
- stop driving
Complications of TIA?
- stroke
- MI
How many TIA patients go on to have a stroke?
Over 10% within 3 months.
What is amaurosis fugax?
Temporary painless blindness affecting one eye, as a result of ischaemia.
Aetiology of amaurosis fugax?
- obstruction of the ophthalmic artery / central retinal artery (branch of the ICA) due to atherosclerotic emboli
- optic neuritis
- giant cell arteritis
Risk factors for amaurosis fugax?
- TIA risk factors (smoking, hypertension, etc)
- giant cell arteritis
Clinical manifestations of amaurosis fugax?
‘Black curtain’ comes across the vision.
Investigations for amaurosis fugax?
- eye examination
- carotid doppler ultrasound
- MR / CT angiography
Management of amaurosis fugax?
- control risk factors (statin therapy, anti-hypertensives. diabetes control)
- anticoagulation therapy (aspirin / clopidogrel)
- carotid stenting / endarterectomy
What is meant by stroke?
Cerebrovascular event caused by reduced / absent blood flow to cerebral tissue, resulting in tissue death. Characterised by sudden onset of focal neurological signs lasting longer than 24 hours.
What is the split between ischaemic and haemorrhagic stroke?
- ischaemic 85%
- haemorrhagic 15%
Causes of haemorrhagic stroke?
- hypertension
- trauma
- anticoagulation
- tumour
- AV malformation
Most common cause of haemorrhagic stroke?
hypertension
Causes of ischaemic stroke?
- thrombosis (atherosclerosis or small vessel disease - vasculitis / sickle cell disease)
- emboli (AF or carotid artery disease)
- dissection (carotid), either spontaneous or secondary to trauma
How does carotid dissection result in ischaemic stroke?
Forms an intramural haematoma that compromises blood flow.
Risk factors for stroke?
- older age
- hypertension
- smoking
- diabetes
- hypercholesterolaemia
- obesity
- AF
- carotid artery disease
- thrombophilic disorders
- sickle cell disease
- vasculitis
Clinical manifestations of a stroke affecting the carotid territory?
- contralateral face / arm / leg weakness
- contralateral sensory loss
- dysphasia
- dysarthria
- homonymous hemianopia
- higher cortical dysfunction
Clinical manifestations of a stroke affecting the posterior circulation territory?
- ataxia
- dizziness
- dysarthria
- diplopia
- diplegia - paralysis affecting symmetrical parts of the body
- cranial nerve palsies
- visual field defects
- isolated homonymous hemianopia
- reduced GCS
Clinical manifestations of a lacunar stroke?
- motor hemiparesis
- ataxic hemiparesis
- ‘clumsy hand’
- dysarthria
May be pure hemisensory, pure motor hemiparesis or mixed sensorimotor.
Clinical manifestations of a haemorrhagic stroke?
More likely to present with global features:
- focal neurological deficitis
- headache
- altered mental status
- nausea and vomiting
- seizures
Investigations for stroke?
- CT head (sensitive for haemorrhage, usually cannot diagnose acute phase infarct)
- MRI brain
- perfusion imaging (CT angiography) to check viable tissue and avoid reperfusion injury
Differentials for stroke?
- TIA
- seizure with Todd’s paresis
- tumour / abscess
- migraine
- hypoglycaemia
Acute management of ischaemic stroke?
- aspirin 300mg (for 2 weeks)
- admit to specialist stroke unit
- IV alteplase for thrombolysis (within 4.5 hours)
- thrombectomy (within 6 hours)
What is the mechanism of action of alteplase?
Tissue plasminogen activator - produces plasmin that lyses fibrin.
Contraindications to alteplase?
- major recent surgery
- bleeding
- severe hypertension
- brain malignancies
Long term management of ischaemic stroke?
- lifestyle changes & stop driving
- occupational therapy & rehabilitation
- clopidogrel 75mg lifelong (after 2 weeks aspirin)
- DOAC for AF
- antihypertensives & statin therapy
Management of haemorrhagic stroke?
- ABCDE, monitor pupil responses and GCS
- correct coagulopathy / reverse anticoagulation
- BP control (acutely aim for < 140-160 systolic)
- neurosurgery
Early complications of stroke?
- seizures
- cerebral oedema
- death
Late complications of stroke?
- motor and sensory deficits
- bladder and bowel dysfunction
- cognitive problems
- visual problems
- psychological problems
- swallowing difficulties
What is a subarachnoid haemorrhage?
Sudden severe headache (‘thunderclap headache’) due to bleeding into the subarachnoid space.
Causes of SA haemorrhage?
- trauma
- aneurysm rupture
- AV malformation
Risk factors for SA haemorrhage?
- age > 50
- female
- smoking
- hypertension
- connective tissue disorders (Marfan’s / EDS)
- family history
- polycystic kidney disease
Clinical manifestations of SA haemorrhage?
- severe sudden onset ‘thunderclap’ headache
- impaired / loss of consciousness
- meningismus (neck stiffness, muscle aches)
- photophobia
- nausea and vomiting
- Kernig’s and Brudzinski’s signs
Investigations for SA haemorrhage?
- CT head shows hyperdense areas in SA space
- lumbar puncture if CT is negative, shows bloody CSF (performed at least 12 hrs after symptom onset)
Management of SA haemorrhage?
- supportive care: intubation and sedation may be required, O2, analgesia
- nimodipine (CCB to prevent delayed cerebral ischaemia)
- neurosurgery (endovascular coiling, surgical clipping)
Complications of SA haemorrhage?
- obstructive hydrocephalus
- arterial vasospasm
- re-bleeding of aneurysm
- long-term neurological deficits
What causes delayed cerebral ischaemia in SA haemorrhage?
Arterial vasospam
Mortality from SA haemorrhage?
50%
What is a subdural haemorrhage?
Collection of blood between the dura mater and arachnoid mater.
Over what time frame may a subdural haemorrhage occur?
- acute (< 3 days)
- subacute (3-21 days)
- chronic (21 days)
Causes of subdural haemorrhage?
- trauma (temporal side of head, causes rupture of bridging veins)
- cerebral aneurysm rupture
- AV malformation rupture
Risk factors for subdural haemorrhage?
- history of trauma / loss of consciousness
- vulnerability to falls (dementia)
- age > 65
- anticoagulation / coagulopathy
- alcohol misuse
Pathophysiology of subdural haemorrhage?
- haematoma volume increases, causing compression and displacement of the brain parenchyma
- ICP rises, which may lead to brain herniation
Clinical manifestations of subdural haemorrhage?
Gradual deterioration:
- headache
- nausea and vomiting
- impaired consciousness / confusion
- ataxia / poor balance
- cranial nerve palsies
- seizures
Investigations for subdural haemorrhage?
- non-contrast CT head (shows crescent shaped collection of blood)
- MRI brain to identify an underlying cause
- coagulation screen
Acute vs chronic subdural haemorrhage appearance on CT?
Acute - hyperdense (white).
Chronic - hypodense.
Management of subdural haemorrhage?
- correct coagulopathy / anticoagulation reversal
- anticonvulsants
- conservative management for small bleeds
- decompressive craniectomy
- burr hole craniotomy for chronic subdural haemorrhage
Complications of subdural haemorrhage?
- permanent neurological deficits
- coma
- seizures
- intracranial infection
- recurrent subdural haematoma
What is an extradural haemorrhage?
Acute haemorrhage between the dura mater and the inner surface of the skull.
Causes of extradural haemorrhage?
Skull trauma in the temporoparietal region (often involves middle meningeal artery) - falls, assault, sporting injuries.
Other causes such as AV malformations and bleeding disorders.
Pathophysiology of extradural haemorrhage?
- as the haematoma grows in volume, it strips the dura mater away from the skull
- ICP increases, leading to midline shift and tentorial herniation, and eventually brainstem death
Clinical manifestations of extradural haemorrhage?
Immediate loss of consciousness, lucid period, then progressive decrease in consciousness.
- headache
- nausea and vomiting
- confusion
- motor / sensory limb defects
- cushing’s triad
Investigations for extradural haemorrhage?
- CT head shows lemon shaped haemorrhage with midline shift
- blood glucose (exclude hypoglycaemia)
Management of extradural haemorrhage?
- correct coagulopathy / anticoagulation reversal
- prophylactic antibiotics
- anticonvulsants
- mannitol / barbiturates to reduce ICP
- burr hole craniotomy
- decompressive hemicraniectomy for large bleeds
Complications of extradural haemorrhage?
- infection
- cerebral ischaemia
- seizures
- hydrocephalus
- brainstem injury
What is the definition of epilepsy?
Condition characterised by recurrent seizures unprovoked by any immediate identified cause.
2 or more unprovoked seizures separated by at least 24 hours.
What is the definition of an epileptic seizure?
Paroxysmal event in which changes of behaviour, sensation, or cognitive processes are caused by excessive, hyper-synchronous neuronal excitation in the brain.
Pathophysiology of epileptic seizures?
Abnormal properties of neurons lead to inappropriate hyperexcitability and hypersynchrony.
Initiation of generalised-onset seizures?
Bihemispheric electrical discharges.
Initiation of focal-onset generalised seizures?
Initially a focal seizure occurs, then the electrical discharges evolve through the ipsilateral hemisphere and cross the corpus callosum to continue in the contralateral hemisphere.
Clinical manifestations of GTCS?
- loss of consciousness
- tonic phase (muscle tensing) followed by clonic phase (muscle jerking)
- tongue biting
- incontinence
- irregular breathing
- post-ictal period where patient is confused, drowsy and irritable / depressed
Investigations for GTCS?
- video EEG (shows generalised epileptiform activity)
- head CT / MRI may show a structural lesion
- lumbar puncture (elevated WCC in CNS infection)
Differentials for GTCS?
- syncope
- cardiac arrhythmia
- transient ischaemic attack
Pharmacological management of GTCS?
Monotherapy with an anticonvulsant - try two different drugs before initiating dual therapy.
- carbamazepine
- lamotrigine
- topiramate
- sodium valproate
Summary of management of GTCS?
- anti-convulsant medication
- surgical resection (in patients with drug-resistant focal onset epilepsy)
- deep brain / vagus nerve stimulation
What are focal seizures?
Seizures arise in one portion of the brain, commonly the temporal lobe. They may affect hearing, speech, memory and emotions.
Pathophysiology of focal seizures?
Hyperexcitability and hypersynchronicity of a group of neurons in one area of the brain.
Clinical manifestations of focal seizures?
- movement of a specific body part
- sense of premonition (fear, deja vu)
- automatisms (lip smacking, clothes picking)
- staring and being unaware of surroundings
- visual, olfactory or gustatory hallucinations
Investigations for focal seizures?
- video EEG
- head CT / MRI for structural abnormalities
- lumbar puncture and CSF fluid analysis for signs of infection
Differentials for focal seizures?
- syncope
- TIA
- tic disorders
- tremor
- dissociative disorders
- migraine
Management of acute focal seizures?
Benzodiazepines (rectal diazepam, intranasal midazolam, oral lorazepam, IV benzodiazepines in hospital).
Long-term anticonvulsant therapy for focal seizures?
Monotherapy of two different drugs, then trial dual therapy:
- lamotrigine
- levetiracetam
- oxcarbazepine
Which anticonvulsants should be avoided in women of child-bearing age?
- sodium valproate
- topiramate
- phenobarbital
- phenytoin
Enzyme-inducing anticonvulsants lower efficacy of the oral combined contraceptive pill (e.g. carbamazepine).
Options for treatment-resistant epilepsy?
- surgical resection of localised epileptogenic area
- neurostimulation (vagus nerve / deep brain stimulation)
What is meant by status epilepticus?
Convulsive seizure lasting > 5 minutes, or repetitive convulsive seizures with no recovery in between.
Causes of status epilepticus?
- anticonvulsant drug withdrawal
- poor anticonvulsant therapy adherence
Pathophysiology of status epilepticus?
- mechanisms that normally abort seizure activity fail, there is excessive and abnormally persistent neuronal excitation
- neuronal injury occurs due to the accumulation of excitatory neurotransmitters
How is status epilepticus managed?
- ABCDE (secure airway, semi-prone position)
- supportive care and monitoring
- IV benzodiazepine (lorazepam)
What is Parkinson’s disease?
Chronic, progressive neurodegenerative condition that occurs secondary to loss of dopaminergic neurones within the substantia nigra.
What is meant by Parkinsonism?
Refers to the presence of bradykinesia and resting tremor / rigidity / postural instability.
Risk factors for Parkinson’s disease?
- male
- older age
- family history
- head trauma
What is meant by ‘on-off’ fluctuations?
Patients switch from dyskinesia to immobility in a few minutes.
What is essential tremor?
Progressive, symmetrical movement disorder of the hands and forearms. Absent at rest, present during intentional movements (particularly anti-gravity positions).
Investigations for essential tremor?
- MRI brain
- DaTscan to distinguish between Parkinson’s and essential tremor
What is Huntington’s disease?
Autosomal dominant neurodegenerative condition - characterised by chorea, dystonia, and cognitive changes.
Cause of Huntington’s disease?
Abnormal expansion of the CAG trinucleotide in the huntingtin gene on chromosome 4.
What is meant by anticipation in Huntington’s disease?
More severe disease develops at an earlier age in offspring.
Pathophysiology of Huntington’s disease?
- CAG expansion leads to an elongated polyglutamine tail on the huntingtin protein
- cleavage and aggregation of this abnormal protein causes neuronal damage
- loss of neurons results in GABA and ACh depletion, dopamine is spared
- primarily affects the striatum (caudate and lentiform nuclei)
What does the lentiform nucleus consist of?
- caudate nucleus
- globus pallidus
Clinical manifestations of Huntington’s?
Development of psychiatric features and cognitive decline, followed by motor features.
Psychiatric features of Huntington’s?
- depression
- paranoia / delusions
- irritability
- impulsivity
- disinhibition
- obsessions and compulsions
- personality change
Cognitive features of Huntington’s?
- impaired work performance
- impaired concentration
- memory loss and dementia
- difficulties with multi-tasking and complex decisions